Bowstring silencer for archery bow

ABSTRACT

A bowstring silencing weight including a bowstring gripping tubular central shaft and a resilient band integral with the central shaft and convoluted therearound to define a spirally wound spring-like coiled ribbon encircling and carried by a bowstring to dampen noise producing vibrations between nodes normally established upon release of a drawn bowstring. The bowstring silencer may also have a plurality of convoluted resilient bands that are attached to the central shaft.

United States Patent Saunders et al.

BOWSTRING SILENCER FOR ARCHERY BOW Inventors: Charles A. Saunders; Francis Eugene Saunders, both of Columbus, Nebr.

Saunders Archery Co., Columbus, Nebr. 1

Filed: Nov. 19, 1973 Appl. No.: 417,139

Assignee:

US. Cl. .1 124/30 A, 273/DIG. 8 Int. Cl. F41b 5/00 Field of Search... 124/30 R, 30 A, 24 R, 23 R,

1 References Cited UNITED STATES PATENTS 6/1971 Stinson 124/30 A [451 Sept. 24, 1974 3,612,029 10/1971 Carroll ..124/30A 3,756,214 9/1973 Christen ..124/30A Primary Examiner-Richard C. Pinkham Assistant Examiner-William R. Browne Attorney, Agent, or Firm-Kegan, Kegan & Berkman [57 ABSTRACT A bowstring silencing weight including a bowstring gripping tubular central shaft and a resilient band integral with the central shaft and convoluted therearound to define a spirally wound spring-like coiled ribbon encircling and carried by a bowstring to dampen noise producing vibrationsbetween nodes normally established upon release ofva drawn bowstring. The bowstring silencer may also have' a plurality of convoluted resilient bands that are attached to the central shaft.

11 Claims, 4 Drawing Figures 1 BOWSTRING SILENCER FOR ARCHERY BOW BACKGROUND OF THE INVENTION tionable in that it startles and causes the game to react so as to lessen the possibility of an effective hit. It is known that the characteristic noise produced upon release of the bowstring is associated with the vibrational pattern set up in the bowstring upon release of the arrow. It is also known that the noise or twang may be' minimized if one is able effectively to dampen the loop oscillations between the nodes of the bowstring. Many devices have heretofore been proposed for the purpose of weighting the bowstring at the principal loops (between the principal nodes), thereby to interfere with the bowstring displacement and to reduce the associated noiser. However, no prior art device has proven completely satisfactory for the intended purpose. It is, therefore, the aim of the present invention to obviate the objectionable features of prior art bowstring silencing devices and to provide an improved silencer which is light in weight, sturdy in construction, effective in use and low in cost.

SUMMARY OF THE INVENTION The bowstring silencer of the invention constitutes a plastic weight of unitary construction which includes a bowstring gripping central shaft portion and a resilient band integrally formed with the shaft and convoluted therearound to define a spirally wound spring-like coiled ribbon which encircles and is carried by the bowstring. In a preferred embodiment of the invention the convoluted coil is a double coil.

It is an important feature of the invention that, upon release of the tensioned bowstring, the bowstring silencer constitutes a fixed mass having inertia which opposes the vibration producing forces applied and that the vibrations are thereby dampened and reduced in the bowstring with a resulting reduction in audible twang.

It is another important feature of the bowstring silencer of the invention that it is formed of high strength plastic material and is sturdy in construction to resist effectively the stresses imposed by the vibration of the supporting bowstring.

Yet another feature of the bowstring silencer of the invention is that it includes a tubular central shaft formed with a passage through which the bowstring passesto facilitate the mounting of the silencer on the bowstring at any selectible position or positions.

Another importantfeature of the silencer of the invention is that it is both small in weight and compact in nature to provide a localized mass contributing to unusually effective silencing capabilities.

It is a general feature of the silencing device of the invention that it is readily and rapidly manufactured and that the cost of production is desirably low to make possible a low sale price.

Yet another important feature of the bowstring silencer of the invention is that the loop quenching" mass of the device primarily is precisely positionable on the bowstring, thereby more effectively to dampen the vibrations.

A related feature of the bowstring silencer is that it is relatively short in its height or vertical dimension as compared with its diametric or horizontal dimension, contributing to a more effective identification of and location of the silencer at the precise point of maximum loop amplitude on the bowstring.

Other objects, features and advantages of the invention will in part be obvious and will become evident upon a consideration of the following specification in conjunction with the drawings.

FIG. 1 is a side elevational view of a strung bow illustrating diagramatically in broken lines the vibrational pattern of the bowstring, and showing a pair of the bowstring silencers of the invention secured at the principal maxima of the loops;

FIG. 2 is an enlarged fragmentary elevational view showing the bowstring silencer of the invention frictionally secured on' the bowstring;

FIG. 3 is a top plan view of a preferred embodiment of the bowstring silencer and illustrating the double convolutes of the spirally wound ribbon-like bands constituting the body of the silencer; and

FIG. 4 is a top plan view of a second embodiment of the bowstring silencer of the invention utilizing a single convolute.

DESCRIPTION or THE PREFERRED r EMBODIMENT Referring nowto the drawing, and particularly to FIGS. 2 and 3, there is shown, for the purpose of illus- I trative disclosure, a preferred embodiment of one form 0f the bowstring silencer of the invention. As illustrated, the silencer constitutes a weight 20 which includes a central shaft or hub 24 formed with a through axial passage 26 for the insertion of a bowstring 30 of a bow 32 therethrough. The shaft 24 is formed of a plastic material which is somewhat resilient and elastic and the axial passage 26 is dimensioned so as to establish a firm frictional engagement between the shaft 24 and the bowstring 30.

Secured to and emanating from the shaft 24 as a spiral or convolute is a spring-like band 34 encircling the shaft 24 and traveling radially helically outwardly from the shaft. A second helical ribbon 40 is fastened to and emanates from the same shaft 24 to define substantially the same general path as the first helical band 34 but spaced radially therefrom throughout substantially its entire course. At their outwardly disposed extremities 44 and 48, the respective coils 34 and 40 taper radially to form thin ends, these ends being fused to the next adjacent coil to provide a margin or peripheral contour which is essentially unbroken and circular. In the preferred embodiment of the silencer illustrated, the fusion positions of the ribbons are diametrically opposed thereby to enhance the balance of the device. At the same time, the connection of the inner extremities of the respective bands 34 and 40 are also diametrically opposed. In the embodiment of the invention illustrated in FIG. 3 the convolute openings or passages bounded by the helical ribbons 34 and 40 are somewhat smaller in radial expanse than is the thickness of the ribbon.

A second embodiment of the invention is shown in FIG. 4. As illustrated, the tubular shaft 52 of the bowstring silencer weight 50 is similar to that of the first embodiment but the body portion differs in that the second embodiment constitutes a single convoluted coil 56. The coil is secured to and emanates from the shaft 52 spiralling outwardly to terminate as a blended fusion 60 of the end portion 62 to the next radially inwardly disposed coil element 66 of the convolute. The resulting coil is generally circular in peripheral contour.

The most important structural feature distinguishing the present invention from prior art silencers is its unique spiral form. This novel structure is effective to bring a unique combination of physical forces into play when the bowstring is released. To facilitate an understanding of the invention it is pointed out that a spiral or spirals eminating from a common point and coiled in the same rotational direction at about the same angular pitch have substantially the same mechanical cha- 1 racterists as one or more concentric and co-planar circles of different diameters. What the spiral arrangement does, in effect, is to hold the circles in the same plane while allowing them to move in relation to their center. The sequential steps in the action of the string silencer of the invention, as the bowstring is drawn and released, are set forth below.

With the bowstring at full draw, the circles of the spiral silencer are centered about the string. When the string is released, the inertia of the circles and the air resistance cause them to lag behind the string displacement and to stretch out, producing generally elipsoid forms. This ability to stretch is an important physical characteristic of the silencer material used in accor dance with the invention. As the bowstring approaches maximum forward speed, the circles tend to catch up and assume a shape or contour close to the starting shape. Then, as the bowstring starts to slow down, the inertia of the circles causes them to advance or go forward with respect to the string. By the time the bowstring has reached its maximum forward displacement and is about to reverse on the first movement of its vibrational mode, the circles of the silencer are close to, but not quite at their maximum forward limit. As the bowstring actually starts back, the silencer circles are out of synchronization with the string; they are still moving forward. Because of the relationship described, the circles absorb some of the energy from the bowstring, cutting down or dampening the vibrational movement. As long as the string trys to move in a vibrational mode, the silencer stays out of sychronization and opposes its movement causing the string vibrations to be highly damped.

The position of the silencer on the string, the number of revolutions of the silencer spiral, the flexibility ofthe silencer, and the ability of the silencer to stretch, all affect the action of the silencer on the string. The mass of the silencer also has an effect in that it helps determine the maximum of energy available for dampening and silencing the string. The actual weight is not so crucial for the silencer of the present invention as it is for those silencers which rely solely on the mass of the silencer to reduce string vibrations. The present silencer not only loads" the string as do all other silencers, but actually dampens the bowstring vibrations by direct interference with its natural vibrational pattern.

it will be evident that the structure of the invention is useful for many applications, in addition to the specific utility as a silencer for bowstrings. For example, the principle may be applied as well to dampen the vibration of steel cables on bridges or other support structures that use rope or cables.

In the preferred embodiments of the bowstring silencer of the invention the coiled band and its central shaft are of plastic material such as polyvinyl chloride or polyurethane molded as a unitary structure, the diametric dimension of the device being greater than the vertical height of the spring-like coils. While disclosures of preferred embodiments of the bowstring silencer and preferred structural materials for producing the device have been provided, it will be apparent that numerous modifications and variations thereof may be made without departing from the underlying principles of the invention. It is, therefore, desired by the following claims to include within the scope of the invention all such variations and modifications by which substantially the results of this invention may be obtained through the use of substantially the same or equivalent means.

What is claimed is:

l. A weight for attachment to a bowstring to constitute a silencer therefor, said weight comprising:

a central shaft having an axial passage for insertion of a bowstring therethrough to effect frictional securement of said weight at selectible positions along the length of the bowstring,

a resilient means of generally spiral configuration coiled about and encircling said shaft for vibrating out of phase with a released bowstring so as to dampen the vibration of a bowstring,

said means comprising a band which is attached to said shaft and gradually receding therefrom radially along a shaft-encircling spiral path.

2. The structure as set forth in claim 1 and further comprising a second band attached to and encircling said shaft,

saidsecond band including coils defininga convolute path around and substantially coextensive with said first band.

3. The structure as set forth in claim 2 wherein respective end portions of said first and second band displaced radially outwardly from said shaft are connected to coils of opposed respective bands thereadjacent.

4. The structure as set forth in claim 3 wherein connections of said end portions of said first and second bands to coils of opposed respective bands thereadjacent are at two positions which are substantially diametrically opposed to one another.

5. The structure as set forth in claim 2 wherein said first and second bands are attached to said shaft at diametrically opposed positions therearound.

6. The structure as set forth in claim 5 wherein respective end portions of said first and said second band are displaced radially outwardly from said shaft and are connected to coils of respective bands thereadjacent at positions substantially diametrically opposite one another to provide a configuration which is essentially bilaterally symmetrical about each of a family of planes in which a longitudinal axis of said shaft lies.

7. The structure as set forth in claim 6 wherein the marginal limits of said weight radially of said shaft define a substantially circular perimeter when said weight is viewed axially of said shaft, in plan.

8. The structure as set forth in claim 7 wherein end portions of respective said bands blend gradually with terminal coils of corresponding opposed bands thereadjacent to be assimilated thereby.

9. The structure as set forth in claim 6 wherein said 5 bands are spaced from one another radially over at least a portion of their generally coextensive paths,

are two such weights are adapted to be fastened to a bowstring at vertically spaced positions therealong, each position corresponding essentially to a point of maximum loop amplitude of a bowstring upon release thereof.

11. The structure as set forth in claim 1 wherein said band constitutes a wound ribbon of resilient plastic generally circular in peripheral contour and adapted to encircle a bowstring,

said ribbon adapted to extend in a zone radially of and normal to a bowstring,

convolutes of said ribbon adapted to project in planes generally paralleling an axis defined by a bowstring. 

1. A weight for attachment to a bowstring to constitute a silencer therefor, said weight comprising: a central shaft having an axial passage for insertion of a bowstring therethrough to effect frictional securement of said weight at selectible positions along the length of the bowstring, a resilient means of generally spiral configuration coiled about and encircling said shaft for vibrating out of phase with a released bowstring so as to dampen the vibration of a bowstring, said means comprising a band which is attached to said shaft and gradually receding therefrom radially along a shaft-encircling spiral path.
 2. The structure as set forth in claim 1 and further comprising a second band attached to and encircling said shaft, said second band including coils defining a convolute path around and substantially coextensive with said first band.
 3. The structure as set forth in claim 2 wherein respective end portions of said first and second band displaced radially outwardly from said shaft are connected to coils of opposed respective bands thereadjacent.
 4. The structure as set forth in claim 3 wherein connections of said end portions of said first and second bands to coils of opposed respective bands thereadjacent are at two positions which are substantially diametrically opposed to one another.
 5. The structure as set forth in claim 2 wherein said first and second bands are attached to said shaft at diametrically opposed positions therearound.
 6. The structure as set forth in claim 5 wherein respective end portions of said first and said second band are displaced radially outwardly from said shaft and are connected to coils of respective bands thereadjacent at positions substantially diametrically opposite one another to provide a configuration which is essentially bilaterally symmetrical about each of a family of planes in which a longitudinal axis of said shaft lies.
 7. The structure as set forth in claim 6 wherein the marginal limits of said weight radially of said shaft define a substantially circular perimeter when said weight is viewed axially of said shaft, in plan.
 8. The structure as set forth in claim 7 wherein end portions of respective said bands blend gradually with terminal coils of corresponding opposed bands thereadjacent to be assimilated thereby.
 9. The structure as set forth in claim 6 wherein said bands are spaced from one another radially over at least a portion of their generally coextensive paths, said bands being resiliently supported on said shaft and being responsive to forces impressed on said weight normally to an axis of said shaft as upon release of a bowstring on which the weight is mounted to oscillate radially with respect to said shaft, thereby establishing interference with a normal vibrational pattern of a bow string to dampen sound-producing vibrations of a bowstring.
 10. The structure as set forth in claim 9 wherein there are two such weights are adapted to be fastened to a bowstring at vertically spaced positions therealong, each position corresponding essentially to a point of maximum loop amplitude of a bowstring upon release thereof.
 11. The structure as set forth in claim 1 wherein said band constitutes a wound ribbon of resilient plastic generally circular in peripheral contour and adapted to encircle a bowstring, said ribbon adapted to extend in a zone radially of and normal to a bowstring, convolutes of said ribbon adapted to project in planes generally paralleling an axis defined by a bowstring. 